Multiple clearance control



June 1,1926. 1,587,013 1 F. VAN D. LONGACRE MULTIPLE CLEARANCE CONTROL Filed Oct. 19, 1925 4 KL 1 K1;

117 Y 2 a If j U 0 1' 2 U 0 x B T i INVENTOR EeaizmfckliflLon awe Patented June l, 1926 UNITED STATES EREDERIcK VAN DUZER LONGACRE, or YonRERs, nEw YORK, ASSIGNOR T0 menu-- soLL-RAND COMPANY, OF JERsEY CITY, NEW

JERSEY.

PATENT: ,oFFIcE.

JERSEY, A CORPORATION OF NEW MULTIPLE oLEARANcE com'RoL.

Application filed October 19, 1925. Serial No. 63,806;

This invention relates to compressors, but more particularly toclearance control for unloading the compressor.

The objectsof the invention are to enable clearance chambers to be simply and conveniently constructed and arranged in such.

manner that the clearance control may be effected in multiple, by first opening a main clearance chamber, and successively opening auxiliary chambers, each communicating with the main chamber in series, but in multiple with each other. By this means multiple series control may also be obtained. In my copending application, Serial No. 63,307, filed October 19, 1925, I have disclosed and claimed mechanism for obtaining series clearance control.

Further objects of the invention will hereinafter appear, and to these ends the invention is shown in one of its referred forms inv the accompanying drawing, WlllCll is a diagrammatic sectional elevation of a compressor cylinder having the invention applied thereto.

Referring to the drawing, the cylinder A is provided with the usual piston B having the piston rod C. Air orfluid to be compressed enters at the inlet 1) and is discharged at the discharge connection E, which may be connected to a suitable re-v ceiver, not shown.

Inlet valves F and discharge valves G are of any suitable and usual construction, in this instance being shown as plate valves. The compressor casing is provided with the main clearance chamber H adapted to communicate with the cylinder A through the valve opening J having a valve seat K which, in this instance, is provided with the valve guide L for the main clearance valve 0. A spring P tends to open the valve, which may be maintained closed in any suitable manner as by means of a pressure fluid device comprising the piston Q operating in the cylinder R and having a piston rod S adapted to bear upon the valve 0. Pressure fluid may be supplied to the cylinder B through the pipe T from any suitable source to maintain the main clearance valve 0 closed, the inner or under side of the piston Q being open to atmosphere through the pipe U.

-Auxiliary clearance chambers V and W,

as shown, are each connected in series with the main clearance chamber'I-I but in multiple or parallel with each other. Valve casings X and Y are interposed between the main clearance chamber H and each of the auxiliary clearance chambers V and W, and auxiliary clearance valves a and 6 similar in construction to the main clearance valve 0 control communication bet-ween the auxiliary chambers V and W and the main chamber H.

In the operation of the device let it be assumed that pressure is relieved from the outer face of the main valve piston Q; through the pipe T, so that the main clearance valve 0 opens under the influence of the spring P assisted by the pressure in the cylinder, in which case the cylinder would be partially unloaded by the main clearance chamberH, which is placed in communicatlon with the cylinder. An additional step of unloading could be obtained by the opening of the auxiliary clearance valve a, which places the auxiliary clearance chamber V in series with the main chamber H. An additional step of unloading will be obtained b the opening of the auxiliary valve 7), which places. the auxiliary chamber W in series with the main chamber II when in parallel with the auxiliary chamber V. By this .means multiple clearance control is obtained for unloading purposes and in addition but in multiple arrangement with each other with respect to said main chamber. Although but two auxiliary clearance chambers V and W are shown, it is to be understood that as many may be used as desired, and series of auxiliary chambers may be arranged in communication with the main chamber but in multiple with each other.

I claim:

1. In a compressor, the combination of a cylinder, inlet and discharge valves, a main clearance chamber, a main clearance valve between said chamber and the cylinder, and auxiliary clearance chambers and clearance valves adapted to communicate in multiple with said main clearance chamber, whereby one or more clearance chambers may be opened for step-by-step unloading.

2. In a compressor, the combination of a cylinder, inlet and discharge valves, a main clearance chamber between said chamber and the cylinder, and auxiliary clearance chambers and clearance valves adapted to communicate in series and multiple with said main clearance chambers, where y one or more clearance chambers may be opened for step-by-step unloading.

3. In a compressor, the combination of'a cylinder, inlet and discharge valves, a main 0 earance chamber, a main clearance valve between said chamber and the cylinder, auxa main clearance valve aeeacia iliary clearance chambers each adapted to communicate directly with the main chamber in series, but in multiple with each other, and auxiliary clearance valves between said 16 auxiliary chambers and the main chamber, whereby multiple series clearance control is obtained for step-by-step unloading.

,In testimony whereof I have signed this specification.

- FREDERICK van DUZEB LONGACRE. 

